Europeans first came to the Western Hemisphere armed with guns, the cross
and, unknowingly, pathogens. Against the alien agents of disease, the
indigenous people never had a chance. Their immune systems were unprepared
to fight smallpox and measles, malaria and yellow fever.

The epidemics that resulted have been well documented. What had not been
clearly recognized until now, though, is that the general health of Native
Americans had apparently been deteriorating for centuries before 1492.

That is the conclusion of a team of anthropologists, economists and
paleopathologists who have completed a wide-ranging study of the health of
people living in the Western Hemisphere in the last 7,000 years.

The researchers, whose work is regarded as the most comprehensive yet, say
their findings in no way diminish the dreadful impact Old World diseases had
on the people of the New World. But it suggests that the New World was
hardly a healthful Eden.

More than 12,500 skeletons from 65 sites in North and South America --
slightly more than half of them from pre-Columbians -- were analyzed for
evidence of infections, malnutrition and other health problems in various
social and geographical settings.

The researchers used standardized criteria to rate the incidence and degree
of these health factors by time and geography. Some trends leapt out from
the resulting index. The healthiest sites for Native Americans were
typically the oldest sites, predating Columbus by more than 1,000 years.
Then came a marked decline.

"Our research shows that health was on a downward trajectory long before
Columbus arrived," Dr. Richard H. Steckel and Dr. Jerome C. Rose, study
leaders, wrote in "The Backbone of History: Health and Nutrition in the
Western Hemisphere," a book they edited. It was published in August.

Dr. Steckel, an economist and anthropologist at Ohio State University, and
Dr. Rose, an anthropologist at the University of Arkansas, stressed in
interviews that their findings in no way mitigated the responsibility of
Europeans as bearers of disease devastating to native societies. Yet the
research, they said, should correct a widely held misperception that the New
World was virtually free of disease before 1492.

In an epilogue to the book, Dr. Philip D. Curtin, an emeritus professor of
history at Johns Hopkins University, said the skeletal evidence of the
physical well-being of pre-Columbians "shows conclusively that however much
it may have deteriorated on contact with the outer world, it was far from
paradisiacal before the Europeans and Africans arrived."

About 50 scientists and scholars joined in the research and contributed
chapters to the book. One of them, Dr. George J. Armelagos of Emory
University, a pioneer in the field of paleopathology, said in an interview
that the research provided an "evolutionary history of disease in the New
World."

The surprise, Dr. Armelagos said, was not the evidence of many infectious
diseases, but that the pre-Columbians were not better nourished and in
general healthier.

Others said the research, supported by the National Science Foundation and
Ohio State, would be the talk of scholarly seminars for years to come and
the foundation for more detailed investigations of pre-Columbian health. Dr.
Steckel is considering conducting a similar study of health patterns well
into European prehistory.

"Although some of the authors occasionally appear to overstate the strength
of the case they can make, they are also careful to indicate the limitations
of the evidence," Dr. Curtin wrote of the Steckel-Rose research. "They
recognize that skeletal material is the best comparative evidence we have
for the human condition over such a long period of time, but it is not
perfect."

The research team gathered evidence on seven basic indicators of chronic
physical conditions that can be detected in skeletons -- namely,
degenerative joint disease, dental health, stature, anemia, arrested tissue
development, infections and trauma from injuries. Dr. Steckel and Dr. Rose
called this "by far the largest comparable data set of this type ever
created."

The researchers attributed the widespread decline in health in large part to
the rise of agriculture and urban living. People in South and Central
America began domesticating crops more than 5,000 years ago, and the rise of
cities there began more than 2,000 years ago.

These were mixed blessings. Farming tended to limit the diversity of diets,
and the congestion of towns and cities contributed to the rapid spread of
disease. In the widening inequalities of urban societies, hard work on
low-protein diets left most people vulnerable to illness and early death.

Similar signs of deleterious health effects have been found in the ancient
Middle East, where agriculture started some 10,000 years ago. But the health
consequences of farming and urbanism, Dr. Rose said, appeared to have been
more abrupt in the New World.

The more mobile, less densely settled populations were usually the
healthiest pre-Columbians. They were taller and had fewer signs of
infectious lesions in their bones than residents of large settlements. Their
diet was sufficiently rich and varied, the researchers said, for them to
largely avoid the symptoms of childhood deprivation, like stunting and
anemia. Even so, in the simplest hunter-gatherer societies, few people
survived past age 50. In the healthiest cultures in the 1,000 years before
Columbus, a life span of no more than 35 years might be usual.

In examining the skeletal evidence, paleopathologists rated the healthiest
pre-Columbians to be people living 1,200 years ago on the coast of Brazil,
where they had access to ample food from land and sea. Their relative
isolation protected them from most infectious diseases.

Conditions also must have been salubrious along the coasts of South Carolina
and Southern California, as well as among the farming and hunting societies
in what is now the Midwest. Indian groups occupied the top 14 spots of the
health index, and 11 of these sites predate the arrival of Europeans.

The least healthy people in the study were from the urban cultures of Mexico
and Central America, notably where the Maya civilization flourished
presumably at great cost to life and limb, and the Zuni of New Mexico. The
Zuni lived at a 400-year-old site, Hawikku, a crowded, drought-prone farming
pueblo that presumably met its demise before European settlers made contact.

It was their hard lot, Dr. Rose said, to be farmers "on the boundaries of
sustainable environments."

"Pre-Columbian populations were among the healthiest and the least healthy
in our sample," Dr. Steckel and Dr. Rose said. "While pre-Columbian natives
may have lived in a disease environment substantially different from that in
other parts of the globe, the original inhabitants also brought with them,
or evolved with, enough pathogens to create chronic conditions of ill health
under conditions of systematic agriculture and urban living."

In recent examinations of 1,000-year-old Peruvian mummies, for example,
paleopathologists discovered clear traces of tuberculosis in their lungs,
more evidence that native Americans might already have been infected with
some of the diseases that were thought to have been brought to the New World
by European explorers.

Tuberculosis bears another message: as an opportunistic disease, it strikes
when times are tough, often overwhelming the bodies of people already
weakened by malnutrition, poor sanitation in urban centers and debilitated
immune systems.

The Steckel-Rose research extended the survey to the health consequences of
the first contacts with American Indians by Europeans and Africans and the
health of European-Americans and African-Americans up to the early 20th
century.

Not surprisingly, African-American slaves were near the bottom of the health
index. An examination of plantation slaves buried in South Carolina, Dr.
Steckel said, revealed that their poor health compared to that of
"pre-Columbian Indian populations threatened with extinction."

On the other hand, blacks buried at Philadelphia's African Church in the
1800's were in the top half of the health index. Their general conditions
were apparently superior to those of small-town, middle-class whites, Dr.
Steckel said.

The researchers found one exception to the rule that the healthiest sites
for Native Americans were the oldest sites. Equestrian nomads of the Great
Plains of North America in the 19th century seemed to enjoy excellent
health, near the top of the index. They were not fenced in to farms or
cities.

In a concluding chapter of their book, Dr. Steckel and Dr. Rose said the
study showed that "the health decline was precipitous with the changes in
ecological environments where people lived." It is not a new idea in
anthropology, they conceded, "but scholars in general have yet to absorb
it."